1. Field of the Invention
The present invention relates to an oxygen enriching module utilizing a plurality of hollow-fibrous membranes permitting a selective permeation of oxygen over nitrogen, and an oxygen enriching apparatus accommodating the oxygen enriching module therein. More particularly, the present invention relates to a compact and light-weight oxygen enriching module and a compact and light-weight oxygen enriching apparatus utilizing the oxygen enriching module.
2. Description of the Related Art
A method of slightly increasing the concentration of oxygen in the air in a house, compared with the atmospheric air, is conventionally applied to obtain a comfortable living environment.
Further, it is known to adopt oxygen inhalation for the treatment of patients suffering from respiratory ailments such as asthma, emphysema, and chronic bronchitis. The conventional oxygen inhalation treatment employs an oxygen enriched air obtained by using an oxygen gas either evaporated from a liquid oxygen obtained by the low temperature processing of air or supplied from conventional gas cylinders. When the enriched air is produced, the oxygen gas is conventionally mixed with and diluted by the atmospheric air, but this dilution of the oxygen gas by mixing it with the atmospheric air is complicated and requires a certain skill when handling the mixing and diluting devices. Therefore, a membrane separating method utilizing the difference in the speeds of permeation of oxygen and nitrogen gases through a membrane formed by using a high molecular weight compound has recently been developed and brought into practical use. Namely, an oxygen enriching apparatus utilizing the membranes permitting a selective permeation of oxygen over nitrogen (hereinafter referred to "oxygen selective permeable membrane") is often used in a medical treatment apparatus for patients suffering from respiratory ailments. Nevertheless, the conventional oxygen enriching apparatuses weigh in excess of ten kilograms, and therefore, it is difficult and tiring to carry these apparatus when using same in different locations.
UK patent application GB 2122103A and European patent application No. 0024718 disclose the employment of hollow-fibrous oxygen permeable membranes for constructing an apparatus for supplying an oxygen enriched gas wherein a plurality of hollow-fibrous oxygen permeable membranes are stationarily held in parallel with one another by a casing, and when air is supplied inside the oxygen permeable membranes through the end openings of the casing, an oxygen enriched air which has permeated through the walls of the hollow-fibrous membranes is obtained from an outlet or outlets of the casing.
The above-mentioned UK and European patent applications are, however, silent about the design and manufacture of a compact and light weight oxygen enriching apparatus.